Our research year is unique in that it is broken up over PGY 2-4; residents have 4-months of research in each of these years. Thus our chiefs are PGY-6. Our research is entirely clinical, rather than laboratory-based. IMHO, this makes it somewhat easier to have multiple children in residency.
Only one female resident at my program has tried - I don't think it's appropriate to extrapolate that to "able." I brought up the fact that she was badass because I think that helped open the minds of the powers that be about the concept of pregnant surgery residents in our program; I think most did not expect her to continue, let alone flourish. The fact that she did so with her first pregnancy had two effects: 1) No one had that much anxiety about the situation when she had her 2nd child and 2) The path will be easier for any future residents who wish to do the same. She's shown that one CAN be a mother AND a great surgery resident. It is possible - the actual performance thereafter is up to the individual resident.
I think it is difficult to do, and the need for maternity leave as well as pregnancy-related complications does make it different for women with regard to the initial physical investment required for biologic reproduction. But who asks male residents if they have a "favorable" situation when bringing up the topic of having kids? Is that even an appropriate question?
Well, my personal experience has been that age does good things for most men, and they only start to be acceptable to my dating standards in their 30s.

Biology certainly plays a role but I'm not sure how the question of one's judgment in the men in their personal life is the concern of the residency program. This oblique characterization of women over the age of 30 without children as somehow desperate or prone to poor judgment in their personal lives does come off as a bit misogynistic, though I have read enough of your posts to believe that was not your express intent.
The decision to pursue surgery is no more or less an impediment to marriage than other individual choices and pursuits a woman makes. In my area at least, it is more difficult to meet desirable men who are interested in dating someone with my kind of job or education level. But... I'm not really interested in dating men who aren't interested in dating women with my kind of job or education level. I also tend to to have the possession of a Bachelor's degree as one of my baseline requirements for considering someone as a prospect, so it's not like the situation is unequal in terms of prejudice.
I don't have a daughter, but I am 31 and I do have a sister who is 15. Do I want her to be a surgeon? I want her to do what makes her happy, overall, without the ridiculous assumption that one can truly "have it all." I think many women of my generation were implicitly told that they could: high-powered job/demanding career and a husband with the same, perfectly kept house without outside assistance, giving dinner parties in pearls, marathon runner/masters level tennis player/etc, 2.5 kids, make every soccer practice/class play/deliver homemade cupcakes/etc. This is insane and has led to a number of fantastic women feeling like they are letting themselves and their families down because they can't do everything. Men don't "do everything" and I'm not sure why the implicit message was different for girls, except that I was born on the heels of the sexual revolution and women were (and are) still trying to balance traditional gender-based societal expectations with modern "feminist" gender-based expectations.
Women are, on the whole, horrible to other women. True feminism should be the freedom to make decisions based on the priorities you set for yourself (or you and your partner set together, if you have one) without constant public and private judgment from non-involved parties. I don't think there's a "War on Women" so much so as a "War Among Women," comparing who's made more or less sacrifice by going to work or staying home or some combination thereof.
The history of my family colors my perspective on this subject. My great-grandmother was born in 1898 and was a graduate of Women's Medical College in Philadelphia; her professors had to sneak in to teach them because otherwise they were ostracized by the medical community at large, for the offense of teaching women. She wanted to be an obstetric surgeon but went into family practice because she was told that women did not go into surgery. She married a fellow physician, but gave up practice when she had her first child. My aunt graduated from medical school in the early 1970s. There were 10 women in her class, due to quotas. She wanted to go into ortho, but was told that it was not a woman's specialty. She went into radiology; her co-residents referred to each other as "Dr." or their last names but they referred to my aunt by her first name or as "The Girl." She was required to tape a sign on the door of her callroom that said "Girl Sleeping In Here." She continued to work after my cousins were born, despite some criticism. She now regularly speaks to sub-specialty surgeons at their conferences on her area of expertise.
My medical school class was 2/3 women and I'm a general surgery resident and no one treats me differently because of my gender (except that one or two of my male attendings seem to be a little skittish that they will somehow inadvertently offend me). 4 of the 12 or so who went into surgery were women. So far, all of us are sticking it out. I see the progress of women in surgery (and having children as a resident) as part of the progress of women overall in the last 100 years. I do think that the idea of trying to balance the demands of a surgical residency and the physical act of gestation and then recovering from childbirth is something that needs to be taken into account; I think the flexibility in the clinical schedule at my program does this well. The biggest hurdles are simply the doubts in the minds of administrators (which are overcome with time and experience with women having children in residency) and women who are unclear on their own priorities or, inappropriately, have guilt over what those priorities are because of some unrealistic notion of what it really means to be a strong and accomplished woman. The world has changed a lot since the 19th Amendment was ratified, but I think we're doing just fine.